Here's a very nice review of the film Stalker.
This film is loosely based on Arkady and Boris Strugatsky's "Road Side Picnic," and Tarkovsky tried, as he did with his "Solaris" (1972), to downplay the science fiction aspect of "Stalker." Except for a brief explanation at the film's beginning, Tarkovsky chooses to ignore the speculations as to what could have created The Zone, and the changes within it.
With "Stalker," Tarkovsky marks the shift toward his later style, with the long takes throughout the film averaging one minute in length, with many four minutes or longer. These long scenes in turn rely heavily on the talent of the actors to sustain the mood, like Writer's long monologue in the sand mogul room. In "Stalker," Tarkovsky is definitively more systematic in his use of black-and-white (sepia) and color stocks than he had been in his previous works. In the swamp scene and Stalker's dream, Tarkovsky reverts to is more usual convention, where dreams are shown in black-and-white, and reality in color. However, the last scene is in color, implying a leakage of the powers of The Zone into the outside reality.
As always in Tarkovsky's films, the natural world is present. Water, which used to be the source of life, a redemptive force and a center of regeneration, is now mostly a symbol of decay and pollution. The only exception is in the dream scene in the swamp, where the water is somewhat restored to its positive symbols. In the last scene in The Zone, the men, resigned to their limitations and weakness, sit outside The Room, as the rain falls inside, gently blocking them from entering.
The wind is associated with the spiritual, and the earth is a positive force. Upon arriving in The Zone, Stalker's first act is to lie down and embrace it, and in the swamp, all three men lay on it. Like a miracle, there is the luxuriant, if dangerous, Nature ever present in the Zone, in contrast to the polluted outside world, where it is totally absent.
And then there is the mysterious dog, which first appears in the swamp scene. Up to this point, the men felt totally alienated from their environment, outside and inside The Zone, and it is at the very moment when they start to meditate and remember, that the dog appears: The Zone is its territory. But at the end of the film, the dog has followed Stalker outside the Zone, showing that even there, the hope that the men were looking for inside The Zone must somehow also exist here, outside, as the dog establishes its own space even though it becomes domesticated in the process.
Although Tarkovsky usually favors classics by such composers as Bach, Pergolesi, or Purcell, the musical score in "Stalker" consists almost exclusively of Eduard Artemiev's electronic music mixed with some folk melodies, contributing efficiently to the hypnotic atmosphere of the film.
The performances of Nikolia Grinko and Anatoly Solonitsyn, as two lost souls in search of an answer, are convincing. Aleksandr Kajdanovsky is outstanding in his role of a tormented and somewhat pathetic Stalker. Although Alisa Frejndlikh's appearance in the film is restricted to only few scenes, there are most powerful.
In "Stalker," Tarkovsky opposes a world in decline, polluted and sterile, to a verdant Zone, which has gotten the better of any human enterprises. He portrays a society which has severed all links with nature, with its own past, and lost its spiritual or moral bearings.
"Stalker" explores the conflict between science, rationalism, materialism, and cynicism versus spirituality, faith, art, and love. The three men embody different philosophical principles. Professor is a rational being who tries to understand the world according to the law of physics. He justifies his going into The Zone as purely scientific curiosity. Writer belongs to those people who cannot accept the world as it is. He is well aware of humanity's decay and of his own as well, but he abhors science, which he does not understand, and would rather look for answers in the supernatural. Writer believes in the redemptive power of art, but he has lost his own inspiration.
Stalker is alone in showing an inclination toward faith. He knows The Zone and has total faith in it, speaking about it as if it were a living being. Stalker respects and fears The Zone at the same time, as he recognizes its potential to provide comfort to the wretched ones who, like himself, have lost all hope, but at the same time it punishes who so ever infringes its rules. This, of course, is how most religious people see their own Gods.
The redemptive power of love is personified by Stalker's wife. Her love and devotion is the final miracle which opposes cynicism and the emptiness of the modern world. All these ideas are clearly expressed at the film's end, as she addresses the audience in her heartfelt monologue.
As the three characters reach The Room, they can ask for their dearest wishes to be granted, but this would require a painful and searching self-examination, with the realization that what they thought they wanted was not exactly what they now really want. For Professor, his true aim was to destroy The Room, which was beyond his scientific understanding. Writer had said that the purpose of his journey was to regain his genius, his inspiration. However, on the threshold of The Room, he realizes that he may not worthy of accepting The Room's gift. As for Stalker, he asks for nothing of The Room, his only purpose to make the trip being to bring hope and happiness to those most retched than he.
"Stalker" is certainly Tarkovsky's most complex and most beautiful film, and is worthy of many viewings to appreciate its aesthetic and depth. Unfortunately, the word limitation of this review does not allow one to explore all the intricacies of this extraordinary film and do it justice.